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A035794 Start of a string of exactly 6 consecutive (but disjoint) pairs of twin primes. 11

%I #112 Jun 24 2022 04:35:55

%S 325267931,412984667,2227604747,2409360557,4014288869,4363839617,

%T 6988064579,8402566787,9497780417,10099096127,12347083739,12429980741,

%U 13022601257,14198015129,14845029299,15330685079,16810761029,17049454841,18266059421,18864084791

%N Start of a string of exactly 6 consecutive (but disjoint) pairs of twin primes.

%H Vasily Danilov, <a href="/A035794/b035794.txt">Table of n, a(n) for n = 1..10000</a>, a(27)-a(41), a(112), a(227)-a(253) from Natalia Makarova, remaining terms from Vasily Danilov and Dmitry Petukhov.

%H Randall Rathbun, <a href="https://listserv.nodak.edu/cgi-bin/wa.exe?A2=NMBRTHRY;6a849ab3.9811">A study of n-twin_prime clusters among prime numbers</a>, Posting to Number Theory List, Nov 19 1998.

%t fQ[n_] := Block[{k = 6}, And[NextPrime[n, -1] - NextPrime[n, -2] != 2, NextPrime[n, 2 k + 1] - NextPrime[n, 2 k] != 2, AllTrue[NextPrime[n, # + 1] - NextPrime[n, #] & /@ (Range[0, 2 k - 1, 2]), # == 2 &]]]; Select[Prime@ Range[10^9], fQ] (* _Michael De Vlieger_, May 09 2015, Version 10 *)

%o (PARI) isok(p) = {if (! isprime(p-2) && isprime(p+2), for (k=2, 6, my(q = nextprime(p+3)); if (! isprime(q+2), return (0)); p = q+2;); q = nextprime(p+3); if (isprime(q+2), return (0)); return (1);); return (0);} \\ _Michel Marcus_, Dec 06 2019

%Y Cf. A001359, A035789, A035790, A035791, A035792, A035793, A035794, A035795, A087641.

%K nonn

%O 1,1

%A _Randall L Rathbun_

%E a(11)-a(17) from _Jud McCranie_, Sep 16 2003

%E Offset corrected by _Arkadiusz Wesolowski_, May 06 2012

%E Wrong term 678771479 deleted and a(18)-a(26) from _Sebastian Petzelberger_, May 04 2015

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Last modified March 29 01:36 EDT 2024. Contains 371264 sequences. (Running on oeis4.)